On Tuesday, NASA's Cassini spacecraft dove between Saturn—the planet it's spent years studying—and the gas giant's rings. This was the second of 22 such maneuvers, the last of which will send Cassini careening into Saturn's atmosphere to meet a fiery end on September 15.

So dark matter is our frenemy. We have no clue what it is. It's kind of annoying. But we desperately need it in our calculations to arrive at an accurate description of the universe. Scientists are generally uncomfortable whenever we must base our calculations on concepts we don't understand, but we'll do it if we have to. And dark matter is not our first rodeo.

Today's spacesuits are designed to work well while astronauts float around outside the International Space Station. But they're not quite right for walking around on the moon or Mars—they're too heavy and don't provide enough flexibility in the hips and knees. That's why NASA is investing in a next-generation spacesuit for exploring deep space.

This may not come as a total surprise, but NASA has announced it's delaying the maiden flight of its super-duper powerful rocket. The Space Launch System (SLS)—destined to carry humankind beyond Earth's orbit, to the moon and Mars—was supposed to launch in late 2018. Now the target has changed to sometime in 2019.

NASA's 20-year Cassini mission is finally coming to a close. After years of orbiting around the Saturn system and collecting some stellar scientific data, the spacecraft is on a path of certain destruction: on Sunday, the probe officially began the last leg of its mission, which will eventually bring it so close to Saturn that the planet's gravity will drag it down and burn it to vapour.

Today, during a phone call with astronaut Peggy Whitson on the International Space Station, President Trump joked that he hoped NASA would land astronauts on Mars by the end of his first term in 2020.